Process for the continuous optical brightening of organic fibre material

ABSTRACT

A PROCESS FOR THE CONTINUOUS, NON-AQUEOUS OPTICAL BRIGHTENING OF ORGANIC FIBRE MATERIAL, ESPECIALLY FIBRE MATERIAL MADE FROM NATURAL OR SYNTHETIC POLYAMIDE, IS DISCLOSED, WHICH COMPRISES IMPREGNATING SAID FIBRE MATERIAL WITH THE SOLUTION OF AT LEAST ONE OPTICAL BRIGHTENER SALT CONSISTING OF AN ANIONIC RADICAL OF AN ANIONIC OPTICAL BRIGHTENER AND AT LEAST ONE ORGANIC NITROGEN COMPOUND CONTAINING AT LEAST ONE NITROGEN ATOM CAPABLE OF SALT FORMATION, IN A SOLVENT OR SOLVENT MIXTURE, THE SOLVENT OR SOLVENT MIXTURE CONSISTING OF UNSUBSTITUTED OR HALOGENATED HYDROCARBON BOILING BETWEEN 50 AND 150*C., AND, OPTIONALLY LIQUID, WATER-SOLUBLE ORGANIC SOLVENT BOILING BELOW 220*C., REMOVING EXCESS SOLVENT FROM THE MATERIAL AND FINISHING THE BRIGHTENING BY A HEAT TREATMENT OF THE IMPREGNATED FIBRE MATERIAL AT TEMPERATURES BELOW THE SOFTENING POINT OF SAID FIBRE MATEIAL. BY THIS PROCESS, ON THE STATED FIBRE MATERIAL VERY EFFECTIVE AND EVEN OPTICAL BRIGHTENINGS HAVING GOOD FASTNESS PROPERTIES, SUCH AS FASTNESS TO DRY CLEANING AND WASHING, ARE OBTAINED.

United States Patent Oflice 3,690,916 Patented Sept. 12, 1972 3,690,916PROCESS FOR THE CONTINUOUS OPTICAL BRIGHTENING OF ORGANIC FIBRE MATERIALHans Wegmuller, Riehen, Alois Kleemann, Base], and

Rudolf Keller, Riehen, Switzerland, assignors to GM- Geigy AG, Basel,Switzerland No Drawing. Filed Apr. 6, 1970, Ser. No. 26,166 Claimspriority, application Switzerland, Apr. 11, 1969,

5,524/69 Int. Cl. C09k 1/02 US. Cl. 117-335 T 9 Claims ABSTRACT OF THEDISCLOSURE A process for the continuous, non-aqueous optical brighteningof organic fibre material, especially fibre material made from naturalor synthetic polyamide, is disclosed, which comprises impregnating saidfibre material with the solution of at least one optical brightener saltconsisting of an anionic radical of an anionic optical brightener and atleast one organic nitrogen compound containing at least one nitrogenatom capable of salt formation, in a solvent or solvent mixture, thesolvent or solvent mixture consisting of unsubstituted or halogenatedhydrocarbon boiling between 50 and 150 C., and, optionally, liquid,water-soluble organic solvent boiling below 220 C., removing excesssolvent from the material and finishing the brightening by a heattreatment of the impregnated fibre material at temperatures below thesoftening point of said fibre material. By this process, on the statedfibre material very eflective and even optical brightenings having goodfastness properties, such as fastness to dry cleaning and washing, areobtained.

The present invention relates to a process for the continuous,non-aqueous optical brightening of organic fibre material, especiallyfibre material made from natural or synthetic polyamide, to thebrightener solutions suitable for the purpose, as well as to the fibrematerial brightened by this process.

It is known that fibre material made from incompletely acylatedcellulose can be brightened by using, amongst others, opticalbrighteners containing sulphonic acid groups, and which are usuallyemployed as sodium salt, by impregnating this material with the solutionof an optical brightener in a water-soluble organic solvent, such aslower alkanols, optionally in admixture with a waterinsoluble organicsolvent, preferably boiling below 250 C., and removing excess solventfrom the material.

It has now been found that it is possible to obtain on organic fibrematerial such as cellulose, polyacrylonitrile fibres, but especially onnatural or synthetic polyamide fibres, appreciably more intensive andmore even brightening effects in a continuous manner by impregnating thefibre material with the solution of at least one optical brightenersalt, consisting of the anionic radical of an anionic optionalbrightener and at least one organic nitrogen compound containing atleast one nitrogen atom capable of salt formation, in a solventconsisting of unsubstituted or halogenated hydrocarbon boiling between50 and 150 C., alone or in admixture with a liquid, water solubleorganic solvent boiling below 220 C., removing a substantial part ofexcess solvent from the material and finishing the brightening by a heattreatment of the impregnated fibre material at temperatures below thesoftening point of the fibre material.

The nitrogen atom, capable of salt formation, of the organic nitrogencompounds, usable according to the invention, can be in the form of aprimary, secondary, tertiary or quaternary amino group. Examples ofparticularly suitable compounds are as follows:

(l) Substituted or unsubstituted aliphatic amines, especiallyalkylamines, such as butylamine, hexylamine, octylamine, decylamine,dodecylamine, tetradecylamine, octadecylamine, diethylamine,dibutylamine, dioctylamine, didodecylamine, N-methyl-N-dodecylamine, Nethyl N- octadecylamine, triethylamine, tributylamine, N,Ndimethyl-N-dodecylamine, N,N-dimethyl N octadecylamine, Bhydroxyethylamine, 'y hydroxypropylamine, N fl-hydroxyethyl Ndodecylamine, 'y methoxypropylamine, N- -methoxypropyl N dodecylamine,N-B-hydroxyethyl-N-octadeeylamine, N,N-dimethyl N benzyldodecylammoniumhydroxide, N,N,N trimethyloctadecylammonium hydroxide andtrimethyldodecylammonium hydroxide.

(2) Substituted or unsubstituted aliphatic diand triamines such as1,2-ethylenediamine, 1,3 propylenediamine, diethylenetriamine, 1,1 bismethyl-propylenediamine, 1,1-bis-dodecylpropylenediamine, 1,1 biscyclohexyl-propylenediamine, l,1-bis-benzyl-propylenediamine,N,N-bis-phenyl-ethylenediamine, N,N,N',N'-tetrapropylpropylenediamine,N,N,N'N tetrabenzylpropylenediamine, N,N,N,N'-tetra-B-hydroxyethylpropylenediamine, l-dodecyl-ethylenediamine, l-octadecyl ethylenediamineand 1-octadecyl-diethylenetriamine.

(3) Substituted or unsubstituted cycloalkylamines such ascyclohexylamine, N-methylcyclohexylamine, N octylcyclo'hexylamine, N Bhydroxyethylcyclohexylamine, N methyl N 13 hydroxyethylcyclohexylamine,dicyclohexylamine, dihydroabietylamine and trimethylcyclohexylammoniumhydroxide.

(4) Substituted or unsubstituted aralkylamines such as benzylamine,fi-phenylethylamine, N-fi-hydroxyethylbenzylamine,N-y-methoxypropylbenzylamine, N-fi-cyanoethylbenzylamine, N-methyl N '7methoxypropylbenzylamine, N-octylbenzylamine, N-octadecylbenzylamine anddibenzylamine.

(5) Substituted or unsubstituted aromatic amines, especially mononucleararomatic amines such an aniline, N- methylaniline, N,N dimethylaniline,N,N-dibutylaniline.

N-fi-hydroxyethyl-N-methylaniline and toluidine.

(6) Unsubstituted or substituted amidines, especially alkylamidines,such as acetamidine, benzamidine, laurylamidine, stearylamidine, as wellas N-methyllaurylamidine, N butyllaurylamidine, N phenyllaurylamidine,N- benzyllaurylamidine, N-methylstearylamidine, N benylstearylamidine,or N-cyclohexylstearylamidine.

(7) Substituted isothioureas, preferably S-alkyl-isothioureas, such asS-benzyl-isothiourea, S-hexyl, S-octyl, S-undecyl, S-dodecyl andS-octadecyl-isothiourea.

(8) Guanidines, especially alkylguanidines, such as phenylguanidine,benzylguanidine, dodecylguanidine and octadecylguanidine.

(9) Hydrazines such as phenylhydrazine or undecylhydrazine.

(l0) N-containing fiveor six-membered heterocycles which can bepartially or completely saturated.

Examples of five-membered N-containing heterocycles are: pyrroles suchas methylpyrrole and benzylpyrrole; pyrrolines such as methylpyrrolineor benzylpyrroline; also pyrrolidines such as methylpyrrolidine,butylpyrrolidine or dodecylpyrrolidine; pyrazoles; pyrazolines such asN-methylpyrazoline; pyrazolidines, especially unsubstituted orsubstituted 2-alkyl-imidazolines, such as 2- heptylimidazoline,Z-undecylimidazoline, Z-heptadecylimidazoline,1-methyl-Z-undecylimidazoline, l-B-hydroxyethyl-2- undecylimidazoline,l-p-hydroxyethyl-2-heptadecylimi-dazoline andZ-aminoethyl-l-heptadecylimidazoline.

Examples of six-membered N-containing heterocycles are: piperidine andits derivatives, especially N-alkylor N-aralkylpiperidine such asN-methylpiperidine, N-dodecylpiperidine and N-benzylpiperidine;piperazines such as N-octadecylpiperazine; morpholine and, inparticular, its

N-alkyl and N-aralkyl derivatives such as N-butylmorpholine,N-octadecylmorpholine or N-benzylmorpholine; quinuclidine and pyridine,N-methylpyridinium hydroxide and octadecycloxy-methylenepyridiniumhydroxide; pyrimidines such as dihydroand especiallytetrahydropyrimidines, preferably 2 alkyltetrahydropyrimidines, such as2-heptyl-tetrahydropyrimidine, Z-undecyl-tetrahydropyrimidine,2-heptadecyl tetrahydropyrimidine,lmethyl-2-undecyl-tetrahydropyrimidine orI-B-hydroxyethyl-2-heptadecyl-tetrahydropyrimidine;Z-amino-l-octadecyl-tetrahydropyrimidine; 1,3,5-triazines, particularlyderivatives of the 2,4,6-triamino-1,3,5-triazine such as 2-dodecylamino-4,6-bis-amino-1,3,5-triazine or2-octadecylamino-4,6-bis-amino-1,3,5-triazine, 2heptadecyl-4,6-bisamino-1,3,5-triazine; or hcxahydro-1,3,5-triazinederivatives.

(11) Condensed N-containing heterocycles such as indolines and indoles.

Preferred organic nitrogen compounds are alkylamines having preferablyfrom 12 to 18 carbon atoms in the alkyl radical such as dodecylamine andoctadecylamine; alkylguanidines having preferably from 12 to 18 carbonatoms in the alkyl radical such as dodecylguanidine oroctadecylguanidine; alkylamidines having preferably from 12 to 18 carbonatoms in the alkyl radical such as N-methylstearylamidine orN-benzyl-lanrylamidine; 2-alkylimidazolines and2-alkyltetrahydropyrimidines having preferably from 11 to 18 carbonatoms in the alkyl radical such as Z-undecyl-imidazoline,2-heptadecylimidazoline, 2-undecyltetrahydropyrimidine and2-heptadecyltetrahydropyrimidine and their l-alkyl derivatives;cycloalkylamines and aralkylamines, such as dicyclohexylainine anddibenzylamine, as well as S-alkyl-isothioureas having preferably from 11to 18 carbon atoms in the alkyl radical such as S-undecyl-, S-dodecylandS-octadecyl-isothiourea.

The use, according to the invention, of the organic nitrogen compounds,as defined, promotes the diffusion of the optical brighteners into thefibres, as a result of which the fastness properties of the brighteningsobtained therewith are in many cases improved.

The anionic optical brighteners usable according to the inventioncontain, as defined, e.g. one or more carboxylic acid groups, butparticularly one or more sulphonic acid groups, and they can belong tovery diverse classes. Particularly brilliant brightening effects areobtained with compounds which are derived from the class of thestilbenes. Suitable derivatives from this class are preferably those of4,4-bis-triazinylamino-stilbene sulphonic acids, stilbylnaphthotriazolesulphonic acids, or 4,4-bis-triazolylstilbene sulphonic acids,especially 4,4-v-triazolylstilbene sulphonic acids.

A further group of preferred brighteners comprises derivatives ofdiaryland triarylpyrazolines containing carboxylic acid and, inparticular, sulphonic acid groups, as well as derivatives ofdibenzothiophenedioxides containing sulphonic acid groups.

Suitable hydrocarbons, boiling between 50 and 150 C., are, e.g. aromatichydrocarbons such as toluene or xylene. Preferably, however,halogenated, especially chlorinated hydrocarbons are used, e.g.chlorobenzene, but particularly, on account of their generally betterregeneration property and noncombustibility, lower aliphatic halogenatedhydrocarbons especially chlorinated hydrocarbons, e.g. chloroform,carbon tetrachloride, trior tetrachloroethylene (perchloroethylene),trifluorotrichloroethane, dichloroethane, trichloroethane,tetrachloroethane or dibromoethylene. It is also possible to usemixtures of such solvents.

Care must be exercised in choosing the solvent or solvent mixture that,with the optimum white-effect, no damage, or minimum damage, to thefibres occurs.

In certain cases, it has proved advantageous to use a solvent mixtureconsisting of from 50 to 99, especially from 80 to 99% by weight ofchlorinated lower aliphatic hydrocarbon boiling between 50 and 150 C.,and from 50 to I, particularly from 20 to 1% by weight of a liquid,water-soluble, organic solvent boiling below 220 C.

By liquid, water-soluble, organic solvents boiling below 220 C. aremeant thermostable solvents which are soluble in water, not to theextent of only fractions of one percent but to the extent of severalpercent. Examples of these are: higher alkanols such as butanols or amylalcohols, cycloaliphatic alcohols such as cyclohexanol, araliphaticalcohols such as benzyl alcohol, or aliphatic or cycloaliphatic ketonessuch as methylethyl ketone or cyclohexanone. Such solvents, as defined,are preferred, however, which are miscible with water in any proportion.Examples of these are: monovalent lower aliphatic alcohols such as loweralkanols, e.g. methanol, ethanol, nor iso-propanol; alkylene glycolmonoalkyl ethers such as ethylene glycol monomethyl or monethyl ether;also furfuryl or tetrahydrofurfuryl alcohol, or divalent aliphaticalcohols such as ethylene glycol or 1,2-propylene glycol; also loweraliphatic ketones such as acetone, lower cyclic ethers such as dioxane;also N,N-dialkylamides of lower monocarboxylic acids such asdimcthylformamide or dimethylacetamide, amides of carbonic acid such asN,N, N,N'-tetramethylurea, cyclic amides such as N-methylpyrrolidone, aswell as mixtures of such liquid, watersoluble, organic solvents.

The composition of the solvent or solvent mixture is governed by thesolubility of the anionic optical brightener or brightener mixture to beused. The composition should be such that a homogeneous and clearbrightener solution is obtained.

Preferred solvent mixtures consist of from to 99% by weight oftrichloroethylene, perchloroethylene or trichloroethane and from 10 to1% by weight of a lower alkanol such as methanol, or of anN,N-dialkylamide of lower monocarboxylic acids, such asdimethylacetamide or dimethylformamide.

The production of the optical brightener salts from the anionic opticalbrightener and the organic nitrogen compound containing at least onenitrogen atom capable of salt formation, can be performed in situ, i.e.in the solvent or solvent mixture itself. Preferably, however, theoptical brightener salts are first produced, in a manner known per se,and then added to the solvent or solvent mixture. In this case, theoptical brightener salts can be prepared by double reaction of thealkali metal or ammonium salts, particularly the sodium salts of theoptical brightener, advantageously in the heat, with a salt of anorganic nitrogen compound, usable according to the invention, with astrong acid, e.g. hydrochloric acid, or by direct neutralisation of theanionic optical brighteners in the form of their free acids with theorganic nitrogen compounds. If the optical brightener salts are preparedin situ, then also the anionic optical brighteners are preferably usedin the form of their alkali metal or ammonium salts, particularly in theform of their sodium salts. The organic nitrogen compound also isadvantageously used in the form of a salt with a strong acid. In thiscase, it is advantageous to remove insoluble constituents, if any, fromthe brightening liquor, e.g. by filtration, before the introduction ofthe fibre material to be brightened.

When anionic optical brighteners are used which are capable of forminganions having two or more negative charges, it is often not necessarythat these charges be completely compensated by the organic nitrogencompound.

The brightener liquor, usable according to the invention, preferablycontains, depending on the type of the optical brightener, from 0.01 to10, especially from 0.1 to 3% by weight of optical brightener.

Suitable organic fibre materials, which can be brightened using theprocess according to the invention, are, amongst others, celluloseesters such as cellulose-2V2- and -triacetate, also high-molecularesters of aromatic polycarboxylic acids with polyfunctional alcohols,e.g.

polyethylene glycol terephthalate, polyurethane, polymeric andcopolymeric acryloand methacrylonitrile, as well as polyolefins such aspolyethylene and polypropylene. The process according to the inventionis suitable, in particular, for the brightening of natural andregenerated cellulose fibres such as cotton or viscose, especially fibrematerial made from natural polyamide such as wool, or preferably madefrom synthetic polyamide such as Polyamide 6.6 and Polyamide 6. Thestated fibre material can be brightened, according to the invention, inany chosen form, e.g. in the form of fiock, slubbing, yarn or--preferablyfabr-ics.

The impregnating of the fibre material is carried out, e.g. by coatingor spraying, particularly, however, by padding. In this case, the fibrematerial is advantageously passed continuously through the brightenerliquor at room temperature and afterwards squeezed out to obtain thedesired content of impregnating solution of about from 30 to 150% byweight, relative to the dry weight of the material. The impregnatedfibre material is then finished by a heat treatment, e.g. attemperatures between 70 and 220 C., optionally after preliminary drying,ad-

SOsNB HOCHzCHn Using the process according to the invention on theorganic fibre material, effective, very even and fast opticalbrightenings, e.g. fast to dry cleaning and washing, 65

are obtained.

Since the technical carrying out of the process enables the solventsused to be recovered and used again in the brightening process, contraryto previously known processes, there is no problem of waste waterpurification. 70

Furthermore, rinsing baths are unnecessary which constitutes a furtheradvantage of the process according to the invention.

The following examples illustrate the invention. The temperatures aregiven in degrees centigrade.

EXAMPLE 1 0.2 g. of the optical brightener salt of the formulaafterwards thermofixed during 30 seconds at 190.

The thus treated substrate exhibits a brilliant whiteeffect.

By using, instead of Polyamide 6.6, cotton cretonne or a fabric madefrom regenerated cellulose or from polyacrylonitrile, proceedingotherwise as stated in the example, a brilliant white-effect is obtainedalso on these materials.

It is possible to brighten, in the same manner, polyethylene glycolterephthalate and cellulose triacetate fabrics.

NH\ /N N N r. 1 2 2 N N N S ot 1 N EXAMPLE 2 1 g. of the opticalbrightener salt of the formula u w-C CH:

CHzCHaOH is dissolved in a solvent mixture consisting of 930 g. oftrichloroethylene and 70 g. of methanol. A knitted fabric made fromPolyamide 6 is impregnated with this solution, as described inExample 1. The impregnated material is afterwards steamed for 5 minutesat 100 to 102.

An even and strong white-effect is obtained on the above mentionedmaterial.

The above optical brightener salt ,is obtained, e.g. as follows:

19.2 g. of the optical brightener of the formula S O Nu S OzNa aredissolved in 2 litres of water at 85 Separately, 4.8 g. of an organicnitrogen compound of the formula are dissolved in 2 litres of water atwith the addition of 2 ml. of 30% hydrochloric acid. These two solutionsare poured together at 50", whereby the salt of the above formula isimmediately obtained as precipitate. The whole is allowed to standovernight, the salt is filtered 75 off on the following day and dried invacuo at 50 to 7 8 EXAMPLE 3 EXAMPLE 16 1 g. of the optical brightenersalt of the formula 0.960 g. of the sodium salt of the opticalbrightener of the formula given in Example 2 are dissolved in 50 g. of

is dissolved in a solvent mixture consisting of 930 g. of methanol.Separately, 0.476 g. of an organic nitrogen trichloroethylene and 70 g.of methanol. With the obcompound of the formula tained clear solution afabric made from Polyamide 6.6

is impregnated at room temperature, the impregnated fabric is squeezedout to obtain a liquor absorption of C Hg;C CHz-HCl about 60%, relativeto the dry weight of the material, and

dried at 40 to 80 in an air-stream. The impregnated and 2 dried fabricis afterwards thermofixed during 30 seconds are dissolved in g. ofmethanol. Both solutions are at 190. 20 combined, well stirred and thendiluted with 930 g. of

An even and strong white-effect is obtained. trichloroethylene. Smallamounts of precipitated sub- By using, instead of a fabric made fromPolyamide 6.6, stances, mainly consisting of sodium chloride, are reafabric or knitted material made from Polyamide 6 or moved by filtration.With the thus obtained solution fabric from polyester, proceedingotherwise as stated in the made from Polyamide 6 is impregnated andsqueezed out example, a brilliant and strong white-effect is likewise toobtain a liquor absorption of 60%, relative to the dry obtained. weightof the material. The impregnated fabric is dried in If the impregnatedPolyamide 6.6 fabric is not thermoan air-stream at 80 and thermofixed at190 for secfixed at 190 but treated with saturated steam at 100 to onds.In this manner an even, brilliant, strong white-effect 102 for 5minutes, then an optical brightening effect of is obtained. equalquality is obtained. 30 EXAMPLE 17 If, in the above example, the 70 g.of methanol are replaced by an equal amount of one of the solventslisted 1 of the optlcal bnghtener salt of the formula N o X l =N on onon NH-CH H HOOH2C2I 80: 03 N/ 2 2 2 J Cfi: \CHI 7 in the following TableI, Column 2, the procedure being is dissolved in a solvent mixtureconsisting of 930 g. of otherwise the same as described in the example,then trichloroethylene and 70 g. of methanol. With this solubrilliantwhite-effects of equal quality are obtained. tion a knitted fabric madefrom Polyamide 6 is impreg- TABLE I nated, as described in Example 1.The material is afterwards steamed for 5 minutes at 100 to 102 and underExample No. Water-miscible solvents about 0.2 atmosphere.

4 Ethanol. An even and strong white-effect is thus obtained on the 5Isopropanol. above mentioned material. 6 Ethylene glycol monomethylether. Instead of Polyamide 6 in the above example a fabric 7Tetrahydrofurfuryl alcohol. made from polyester or from Polyamide 6.6can be used. 8 Dimethylacetamide. Also on these materials, aftersteaming at 100 to 102 dur- 9 N,N,N',N'-tetramethyl urea. ing 5 minutes,a beautiful, strong white-etfect is obtained. 10 Dioxane. 11N-methylpyrrolidone. EXAMPLE 18 12 Dimethylformamide 1 g. of the opticalbrightener salt of the formula If, i E l 3 to 12 i t d f 930 f i hl r isdissolved in a solvent mixture consisting of 930 g. of triethylen thosame amount of one of [he hydrocarbons or chloroethylene and g. ofmethanol. With thlS solution 3. chlorinated hydrocarbons given in thefollowing Table II, fabric made from Polyamide 6 is impfegnated- The c l2 i d, i h th i h Same procedure brightening is afterwards thermofixedfor 30 seconds at as described in this example, then likewise even andwell 190. developed optical brightenings are obtained. A strongwhite-effect is obtained on this material.

70 If, instead of thermofixing the impregnated fabric at TABLE H 190, itis treated with saturated steam at 100 to 102 for Example No.Hydrocarbon or chlorinated hydrocarbon 5 minutes, then a brighteningeffect of equal quality is 13 Toluene. obtained.

14 Xylene. If, instead of the brightener salt given in the above ex- 15Tetrachloroethylene. ample, the same amount of one of the brightenersalts given in the following Table III, Column 2, is used, the thensimilar brightening eifects on Polyamide 6 fabric are procedure beingotherwise as described in the example, obtained.

TABLE III Ex. No. Optical brightener salts 11 12 TABLE IIIContlnuetl Ex.No. Optical brightener salts 01s $0. a a

omo-Q-oo-mr NH-CO-Q-QCm CnHu- \N-H S0: N J NH 1 a1...

/ NH "'89 -Q1 32 NH-CzH;

IVE-C2115 /N HOCHzCHn 19.2 g. of the sodium salt of the opticalbrightener of the formula given in Example 2 are dissolved in 2 litersare dissolved in a solvent mixture consisting of 900 g. of 45 of waterat 85. Separately, 10.16 g. of a compound of the trichloroethylene and100 g. of dimethylacetamide. With this solution a knitted fabric madefrom Polyamide 6 is impregnated as described in Example 1. Theimpregnated knitted fabric is afterwards steamed for minutes at atemperature of 100 to 102.

An even, strong white-effect is obtained on the above mentionedmaterial.

If a fabric made from cellulose triacetate is treated with the abovementioned solution, the procedure being otherwise as stated, then onthis material too a strong whiteelfect is obtained.

If a fabric made from cellulose-2 /z-acetate is padded with the abovesolution, the fabric squeezed out to obtain a liquor absorption of 60%,relative to the dry weight of the material, and the material thentreated for seconds at 160, cellul0se-2 /z-acetate fabric having abeautiful even white-effect is obtained.

0 formamide.

formula (J li -C NH-C(H9 are dissolved in 2 litres of water at with theaddition of 4 ml. of 30% hydrochloric acid. These two solutions arecombined at whereby the formed salt immediately precipitates. The wholeis allowed to stand overnight, the salt is filtered ofi on the followingday and dried in vacuo at 50 to 60.

This optical brightener salt is very easily soluble, e.g. in methanol,ethanol, benzyl alcohol and in dimethyl- EXAMPLE 34 1 g. of the opticalbrightener salt of the formula 6 OS N-N NIH-I The above opticalbrightener salt is obtained, e.g. as follows:

is dissolved in a solvent mixture consisting of 930 g. of

75 trichloroethylene and g. of methanol. With this solu- 14 tion afabric made from Polyamide 6.6 is impregnated at In the above example,instead of a knitted material room temperature, the impregnated fabricis squeezed out made from Polyamide 6, also a fabric made from polytoobtain a liquor absorption of about 60%, relative to ester or Polyamide6.6 can be used. After steaming at 100 the dry weight of the material,and dried at 40 to 80 to 102 for minutes, with otherwise the sameprocedure in an air-stream. The impregnated and dried material is 5 asindicated above, also on these materials a beautiful, afterwardsthermofixed during 30 seconds at 190. strong white-effect is obtained.

An even and stron white-effect is obtained in this mang EXAMPLE 37 If,instead of a fabric made from Polyamide 6.6, a 1 g. of the opticalbrightener salt of the formula -OH=CHN-N e03 N c,,rr23 o em-n NHCH2 Jfabric made from Polyamide 6 or from polyester is used, is dissolved in999 g. of tetrachloroethylene. With the the procedure being otherwise asdescribed above, then Obtained clear solution a fabric made fromPolyamide 6.6 also a brilliant, strong white-effect is obtained. isimpregnated at room temperature, the impregnated If the impregnatedPolyamide-6.6-fabric is not thermofabric is squeezed out to obtain aliquor absorption of fixed at 190 but treated with saturated steam at100 to about 60%, relative to the dry weight of the material, 102 for 5minutes, then an optical brightening elfect of and dried at 40 to 80 inan air-stream. The impregnated equal quality is obtained. and driedmaterial is afterwards thermofixed during seconds at 190. EXAMPLE 25 Aneven and strong white-effect is obtained in this 1 g. of the opticalbrightener salt of the formula manner.

is dissolved in a solvent mixture consisting of 900 g- 35 If theimpregnated Polyamide-6.6-fabric is not thermo- Of flichlmoethylene and100 of methanol- With this fixed at 190 but treated with saturated steamat 100 to solution a k tted material made from Polyamide 6 is 102 for 5minutes, then an optical brightening etfect of impregnated as describedin Example 1. The impregnated equal quality is obtained.

material is then steamed at 100 to 102 and about 0.2

atmosphere for 5 minutes. 0 EXAMPLE 38 An even and strong white-effectis obtained on the above-mentioned material. 2 g. of the opticalbrightener salt of the formula N- H xe C 2...: HOGH2C2 CHHCHZOH In theabove example, instead of a knitted material are dissolved in a solventmixture consisting of 9 20 g. made from Polyamide 6, also a fabric madefrom polyof tetrachloroethylene and 80 g. of dimethylacetamide. ester orPolyamide 6.6 can be used. After steaming at Wlth the obtained clearsolution a fabric made from 100 to 102 for five minutes, with otherwisethe same Polyamide 6.6 is impregnated as described in Example 1.procedure as indicated above, also on these materials a The impregnatedmaterial is afterwards steamed for five beautiful, strong white-effectis obtained. minutes at a temperature of 100 to 102.

EXAMPLE 36 An even, strong whlte-effect 1s obtalned on theabovementioned material. 1 g. of the optical brightener salt of theformula a. N N a I a Q H H C C1 :1 an

CH-C a NHGHQJ is dissolved in 999 g. of trichloroethylene. With thissolu- What we claim is: tion a knitted material made from Polyamide 6 isim- 1. A process for the continuous, non-aqueous optical pregnated asdescribed in Example 1. The impregnated brightening of organic, fibrematerial, comprising: material is then steamed at 100 to 102 and about0.2 (a) impregnating said fibre material with the solution atmospherefor 5 minutes. of at least one optical brightener salt consisting of anAn even and strong white-effect is obtained on the anionic radical of ananionic optical brightener and above-mentioned material. at least oneorganic nitrogen compound containing at least one nitrogen atom capableof salt formation, selected from the group consisting of alkylamineshaving from 12 to 18 carbon atoms in the alkyl radical, alkylguanidineshaving from 12 to 18 carbon atoms in the alkyl radical, alkylamidineshaving from 12 to 18 carbon atoms in the alkyl radical, 2-alkylimidazolines and 2-alkyl-tetrahydropyrimidines having from 11 to 18carbon atoms in the alkyl radical, cycloalkylamines, aralkylamines, andS-alkylisothioureas having from 8 to 18 carbon atoms in the alkylradical.

(I) in a solvent selected from unsubstituted or halogenated hydrocarbonshaving a boiling point between 50 and 150 C., or

(II) in a solvent mixture which consists of (a) unsubstituted orhalogenated hydrocarbons having a boiling point between 50 and 150 C.,and

(/3) a liquid, water-soluble, organic solvent boiling below 220 C., andselected from the group consisting of alkanols, cycloaliphatic alcohols,araliphatic alcohols, aliphatic and cycloaliphatic ketones, alkyleneglycol monoalkyl ethers, furfuryl alcohol, tetrahydrofurfuryl alcohol,divalent aliphatic alcohols, lower cyclic ethers, N,N- dialkylamides oflower monocarboxylic acids, amides of carbonic acid, cyclic amides andmixtures thereof,

(b) removing a substantial part of excess solvent from the material, and

(c) finishing the brightening by a heat treatment of the impregnatedfibre material at temperatures below the softening point of said fibrematerial.

2. A process as described in claim 1, characterised by the use ofderivatives of 4,4'-bis-triazinylaminostilbene sulphonic acids,stilbylnaphthotriazole sulphonic acids, 4, 4'-bis-triazolylstilbenesulphonic acids or of derivatives of diaryland triarylpyrazolinescontaining carboxylic acid or sulphonic acid groups.

3. A process as described in claim 1, wherein the solvent defined under(I) consists of lower aliphatic halogenated hydrocarbons.

4. A process as described in claim 3, wherein said solvent istrichloroethylene, perchloroethylene or trichloroethane.

5. A process as described in claim 1, wherein the solvent mixturedefined under (II) consists of (a) from to 99% by weight of chlorinated,lower aliphatic hydrocarbon boiling between 50 and 150 C., the balanceconsisting of (,3) a liquid, water-soluble, organic solvent boilingbelow 220 C., and selected from the group consisting of alkanols,cycloaliphatic alcohols, araliphatic alcohols, aliphatic andcycloaliphatic ketones, alkylene glycol monoalkyl ethers, furfurylalcohol, tetrahydrofurfuryl alcohol, divalent aliphatic alcohols, lowercyclic ethers, N,N-dialkylamides of lower monocarboxylic acids, amidesof carbonic acid, cyclic amides and mixtures thereof.

6. A process as described in claim 5, wherein the water-soluble organicsolvent defined under II(fl) is selected from the group consisting ofmethanol, ethanol, n.propanol, isopropanol, butanol, pentanols,cyclohexanol, benzyl alcohol, acetone, methylethyl ketone,cyclohexanone, ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethyleneglycol, 1,2-propylene glycol, dioxane, dimethylformamide,dimethylacetamide, N,N,N',N'-tetramethyl urea, N-methylpyrrolidone, andmixtures of such solvents.

7. A process as described in claim 5, characterised by the use of asolvent mixture consisting of from to 99% by weight oftrichloroethylene, perchloroethylene or trichloroethane, the balanceconsisting of methanol, dimethylacetamide or dimethylforrnamide.

8. A process as described in claim 1, wherein the impregnated fibrematerial is subjected to a moist heat treatment.

9. A process as described in claim 1, characterised by the use ofnatural or synthetic polyarnide fibres as organic fibre material.

References Cited UNITED STATES PATENTS 2,972,611 2/1961 Zweidler et al.117-335 T 2,784,184 3/1957 Zweidler et a1 260240 C 3,459,744 8/1969Dorlars et al 117-335 T 3,496,112 2/1970 Goldwasser et al. 11733.5 T

RALPH S. KENDALL, Primary Examiner U.S. Cl. X.R.

